On Tue, Jun 18, 2013 at 9:54 PM, Andres Freund <andres@2ndquadrant.com> wrote:
> Hi,
>
> On 2013-06-18 11:35:10 +0200, Andres Freund wrote:
>> Going to do some performance tests now.
>
> Ok, so ran the worst case load I could think of and didn't notice
> any relevant performance changes.
>
> The test I ran was:
>
> CREATE TABLE test_toast(id serial primary key, data text);
> ALTER TABLE test_toast ALTER COLUMN data SET STORAGE external;
> INSERT INTO test_toast(data) SELECT repeat('a', 8000) FROM generate_series(1, 200000);
> VACUUM FREEZE test_toast;
>
> And then with that:
> \setrandom id 1 200000
> SELECT id, substring(data, 1, 10) FROM test_toast WHERE id = :id;
>
> Which should really stress the potentially added overhead since we're
> doing many toast accesses, but always only fetch one chunk.
Sounds really good!
Regards,
--
Fujii Masao